The biosynthesis of the cardenolid- and spirostan glycoside in Digitalis lanata EHRH. Comparison of formation rates. Glycoside and aglycone, 274

Young plants of Digitalis lanata were fed by the vick technique with ammonium mevalonate-[3-¹⁴C]. The isolation from the leaves of pure digitoxigenin and gitoxigenin (without dilution) was described formerly [5]. We describe here the isolation from the same plants of the four pure spirostanols: tigogenin ( 5 ), digalogenin ( 6 ), gitogenin ( 7 ) and digitogenin ( 8 ), again without dilution. These spirostanols contained about 3–5 times more radioactivity per Mol than the cardenolides.     

Bioactivity-guided isolation of new antiproliferative compounds from Juniperus foetidissima Willd.

Based on a literature survey on cytotoxic medicinal plants, Juniper species were identified as interesting source of antitumor compounds. Using bioassay-guided fractionation against Caov-4 cancer cells on acetone extract of leaves and branchlets of Juniperus foetidissima led to the isolation of a new 3H-benzofuaran-2-one: 4-methyl-3-methoxy-3H-benzofuaran-2-one (1), a new sesquiterpene: 4,9(α)-dihydroxy-nardosin-6-en (2) and an already known labdane-type diterpene: 15-hydroxy-8(17),13(E)-labdadiene-19-carboxilic acid (3). Compounds 1–3 exhibited cytotoxic effects, with moderate cytotoxicity against the EJ-138 bladder and CAOV-4 ovary cancer cell lines.     

Carrageenan as an elicitor of induced secondary metabolites and its effects on various growth characters of chickpea and maize plants

The effects of polysaccharide elicitor k-carrageenan obtained from Hypnea musciformis, red algae on the production of Induced Secondary Metabolites, ISMs (the disease resistance compounds) and on various growth characters of chickpea and maize plants were studied. Experiments were conducted in the field of PCSIR Laboratories Complex Karachi during December 2008–April 2009 in randomized complete block design with three replications. Three elicitor treatments were used, a solid preparation in which the elicitor was mixed with soil (T₂ 1 mg/g) and applied around the seeds in the soil. The two other preparations were liquid, T₁ and T₃ at a concentration of 100 μg glc eq ml⁻¹ and were applied around the sowing seeds and as a foliar spray on the plants, respectively. Statistical analysis of the data revealed that these treatments significantly enhanced all the growth characters of chickpea except T₂ that gave the nonsignificant difference in the plant height. Maximum plant height (80.3 cm), number of pods plant⁻¹ (76.2), number of branches plant⁻¹ (25.0), number of leaves plant⁻¹ (125.6), earlier flowering and high ISMs contents in leaves, stem and grains of chickpea were recorded in T₁ treated chickpea plants. In maize plants only T₁ and T₃ treatments (with minor exceptions) had significant effects on few characters like plant height, stem diameter, number of leaves plant⁻¹ and on ISMs contents in leaves while number of cobs plant⁻¹ and flowering time were nonsignificantly affected by these treatments. These results suggested that k-carrageenan elicitor can be used as a potent plant protectant as well as growth promoting agent especially for chickpea plants.     

Phytoremediation of arsenic by two hyperaccumulators in a hydroponic environment

Phytofiltration involves the use of plants to remove toxic compounds from water. Arsenic is an element of considerable environmental and toxicological interest because of its potential deleterious effects upon human health. In this research, a laboratory-constructed hydroponic system was employed to characterize phytofiltration for the uptake of arsenic and macronutrients by two arsenic hyperaccumulators, Pteris cretica cv Mayii (Moonlight fern) and Pteris vittata (Chinese brake fern). Arsenic was shown to preferentially accumulate in the leaves and stems of P. cretica cv Mayii compared to roots. The amounts of the macronutrients calcium and phosphorous absorbed were compared for control plants (growth solution) and plants exposed to arsenic(III) (growth solution and arsenic(III)). Significant differences in the concentration levels of the macronutrients were observed in roots, stems, and leaves between the control and arsenic-exposed plants. The arsenic contents of entire P. vittata plants exposed to hydroponic solutions containing arsenic(III) and arsenic(V) were compared, and no significant difference was observed.     

Flavonoid Composition in the Leaves of Twelve Litsea and Neolitsea Plants

This study was aimed to study the chemodiversity of flavonoids in the Formosan Litsea and Neolitsea plants. Applications of LC‐SPE‐NMR and LC/MS hyphenated techniques in analyzing polar constituents from the leaves of L. acuminata, L. hypophaea, N. acuminatissima, and N. konishii led to the identification of 13 known flavonoids and one new flavonol dioside, quercetin 3‐O‐(2‐O‐β‐D ‐apiofuranosyl)‐α‐L ‐rhamnopyranoside. The quantity and variety of flavonoid composition in the leaves of 12 Litsea and Neolitsea plants were examined to enable more effective utilization of such bioactive ingredients. Of these, N. acuminatissima was found to contain the most quantity of flavonoids (ca. 0.24%leaves).     

The Effects of Ambient Solar UV Radiation on Alkaloid Production by Erythroxylum novogranatense var. novogranatense†

Truxillines are alkaloids produced by Erythroxylum species and are thought to be derived from the UV‐driven dimerization of cinnamoylcocaines. This study was conducted to determine the effects of ambient UV radiation on the production of truxillines in Erythroxylum novogranatense var. novogranatense. Field plants were grown under shelters covered with plastic filters that were transparent to UV radiation, filtered UV‐B, or both filtered UV‐B and UV‐A radiation. The treatments had no significant effect on plant biomass or specific leaf weight. Absorption values in the UV‐C and UV‐A region of acidified‐methanol leaf extracts were higher for plants exposed to UV radiation compared to the no UV radiation treatment. There was a trend in decreasing levels of trans‐cinnamoylcocaine and a statistically significant decrease in levels of cis‐cinnamoylcocaine in the leaves of plants exposed to UV radiation compared to the no UV radiation treatment. Truxilline levels increased in leaves from plants exposed to UV radiation compared to the no UV radiation treatment. Most significantly, the ratio of truxillines to total cinnamoylcocaines in the leaves was affected by UV, increasing with increased UV exposure. The results support the hypothesis that UV radiation is involved in the formation of truxillines from cinnamoylcocaines.     

Formation of the First Trimeric Monoterpenoid Indole Alkaloids

Under O², the Aspidosperma alkaloid tabersonine ( 1 ) was converted by a crude enzyme preparation from leaves of mature plants of Catharanthus roseus G DON into the trimeric 3-hydroxy-14′-(3α″-tabersonyl)voafrine B ( 4 ) which was easily reduced by NaBH₄ to 14′-(3α″-tabersonyl)voafrine B ( = tertabersonine; 5 ). Compounds such as 4 and 5 are the first trimeric alkaloids in the series of monoterpenoid indole alkaloids.     

Secolridoids Glycosides from Jasminum amplexicaule

In addition to jaslanceosides B ( 1 ) and E ( 2 ), and jasminoside ( 3 ), a new secoiridoid glucoside, isojasminoside ( 4 ) was isolated from the leaves of Jasminum amplexicaule (Oleaceace). The structure of 4 was determined on the basis of spectral analysis and chemical reactions. Chemotaxonomy for some selected plants in Jasminum is also discussed.     

Occurrence of methylated arsenic species in parts of plants growing in polluted soils

Arsenic compounds were determined in extracts of branches, leaves and roots from plants growing in a mining contaminated area. The selected species were Dryopteris filix-max, Quercus pubescens, Dipsacus fullonum, Alnus glutinosa, Buxus sempervirens and Brachythecium cf. reflexum. Total arsenic content in the subsamples was analysed by ICPMS after acidic digestion. In general, concentrations in the plant parts followed the gradient roots?>?branches?>?leaves indicating that they are arsenic-resistant plants. Arsenic species were determined in water/methanol (9?+?1, v/v) extracts by HPLC-ICPMS. Different levels of organoarsenicals were found depending on plant part and plant species. Higher percentages of organoarsenic compounds were recorded in branches and leaves (up to 35% in the boxtree sample), than in roots (0.7–5.2% in the same plant species). The absence of organic arsenic species in the soil where the plants were collected and the low levels of organoarsenicals found in the roots, indicate that the studied plants have the ability to accumulate or synthesise organoarsenic compounds in relatively high percentages, and this information contributes to enlarge the knowledge of arsenic uptake and speciation in plants.     

Comparative analysis of essential oil compositions from leaves and stems of Rhododendron adamsii, R. aureum, and R. dauricum

Chemical compositions of essential oils (EO) from leaves and stems of Rhododendron adamsii, R. aureum, and R. dauricum were studied by GC/MS. The analysis demonstrated that the EO of these plants contained mainly mono-and diterpene hydrocarbons. A large amount of alkanes was also found in the EO of R. aureum. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 344–347, July–August, 2006.     

Isolation,purification, and identification of the main phenolic compounds from leaves of celery (Apium graveolens L. var. dulce Mill./Pers.)

We developed a simple and meaningful preparative method for the separation and purification of the main phenolic compounds from the leaves of celery (Apium graveolens L. var. dulce Mill./Pers.) and we established an accurate and specific analytical method for the identification of the main phenolic compounds from celery leaves. The crude extract from celery leaves was prefractioned by polyamide resin to enrich the phenolic compounds. They were then purified further by preparative high‐performance liquid chromatography, and seven main phenolic compounds were obtained: including chlorogenic acid, luteolin 7‐O‐β‐d‐ apiofuranosyl(1→2)‐β‐d‐ glucopyranoside, luteolin 7‐O‐β‐d‐ glucopyranoside, apiin, chrysoeriol 7‐O‐β‐d‐ apiofuranosyl(1→2)‐β‐d‐ glucopyranoside, luteolin 7‐O‐[β‐d‐ apiofuranosyl(1→2)‐(6′′‐O‐malonyl)]‐β‐d‐ glucopyranoside, and apigenin 7‐O‐[β‐d‐ apiofuranosyl(1→2)‐(6′′‐O‐malonyl)]‐β‐d‐ glucopyranoside. Their purities were measured by using high‐performance liquid chromatography, and their chemical structures were confirmed using UV spectrophotometry, ultra high performance liquid chromatography with quadrupole time‐of‐flight tandem mass spectrometry, and NMR spectroscopy. Our studies indicate that preparative high‐performance liquid chromatography combined with polyamide resin is a simple and meaningful preparative method for the separation and purification of phenolic compounds from the leaves of celery or other plants, and the use of UV spectrophotometry, ultra high performance liquid chromatography with quadrupole time‐of‐flight tandem mass spectrometry, and NMR spectroscopy is an accurate and specific analytical method for the identification of phenolic compounds.     

High Levels of Expression of Fibroblast Growth Factor 21 in Transgenic Tobacco (<Emphasis Type="Italic">Nicotiana benthamiana)</Emphasis>

Fibroblast growth factor-21 (FGF21) is a hepatic hormone that plays a critical role in metabolism, stimulating fatty acid oxidation in the liver and glucose uptake in adipose tissue. In this study, we produced tobacco plants expressing human recombinant FGF21 (hFGF21) via Agrobacterium-mediated transformation using a potato virus X (PVX)-based vector (pgR107). The vector contained the sequence encoding the human FGF21 gene fused with green florescence protein and a histidine tag. The recombinant plasmid was introduced into leaf cells of Nicotiana benthamiana (a wild Australian tobacco) via Agrobacterium-mediated agroinfiltration. As determined by fluorescence and Western blot of leaf extracts, the hFGF21 gene was correctly translated in tobacco plants. Seven days after agroinfection, the recombinant hFGF21 had accumulated to levels as high as 450 μg g⁻¹ fresh weight in leaves of agroinfected plants. The recombinant hFGF21 was purified from plant tissues by Ni–NTA affinity chromatography, and the purified hFGF21 stimulated glucose uptake in 3T3/L1 cells. This indicated that the recombinant hFGF21 expressed via the PVX viral vector in N. benthamiana was biologically active.     

Study of the effect of uranium and thorium on the growing of pepper (<Emphasis Type="Italic">Capsicum annuum var. longum</Emphasis>) and cucumber (<Emphasis Type="Italic">Cucumis sativus</Emphasis>) plants

The transportation rate of uranium and thorium to different plants grown in soils having high level of these elements varies closely with the plant characteristics. In this study, the pepper (Capsicum annuum var. longum) and cucumber (Cucumis sativus) plants were chosen as vegetables which are commonly consumed over different regions by different populations. The results obtained can be summarized as follows. (1) High uranium concentration in the soil prevents the growing of the plants. Only the plants in the pot having the uranium concentration of about 263 ppm grew significantly. The plants in other pots having a higher concentration turned pale and died in a few weeks. (2) In the pot having thorium level of about 263 ppm, the plants were well grown and fruited in comparison to the control plants, but the increase of thorium concentration inversely influenced their growing. (3) The gross activities measured in different parts of the plants were not particularly high, however, in both cases the maximum activities were measured in the stems rather than in the fruits and leaves. (4) The plants grown in soils having thorium content lived longer than the control plants and at the greenhouse conditions indicated above, all plants lived more than one whole year flowering and fruiting.     

Structural studies of the chemical constituents of Tithonia tagetiflora Desv. (Asteraceae)

Tithonia tagetiflora Desv. (Asteraceae) is a widespread plant in Vietnam, and the species of Tithonia are known as plants containing many biologically active compounds. However, T. tagetiflora's chemical composition remains mostly unknown. Therefore, we now report the structural elucidation of two new sesquiterpene lactones, 8‐angeloyloxy‐2,14‐epoxygermacra‐4,10(1),11(13)‐trien‐6,12‐olide (1) and 6‐angeloyloxy‐1‐hydroxy‐3,4‐epoxygermacra‐9,11(13)‐dien‐8,12‐olide (2), together with three known compounds, including two norisoprenoids, (6S,9S)‐vomifoliol or (6R,9R)‐vomifoliol (3) and (6S,9S)‐roseoside (4), and one glutinane type triterpene, epi‐glutinol (5), from the leaves of T. tagetiflora. Their structures are established by 1D and 2D NMR spectroscopy, as well as ESI‐MS analysis and comparison with literature data. Copyright © 2013 John Wiley & Sons, Ltd.     

Changes in the Leaf Surface Chemistry of Apium graveolens (Apiaceae) stimulated by jasmonic acid and perceived by a specialist insect

Treatment of celery leaves (Apium graveolens, cv. secalinum) with Jasmonic acid (JA, 1 ) or analogues of amino-acid conjugates of Jasmonic acid such as the leucine conjugate with 1-oxoindan-4-carboxylic acid (IN-ILE, 2 ) stimulated the biosynthesis of the furanocoumarins psoralen ( 6 ), xanthotoxin ( 8 ), bergapten ( 7 ), and isopimpinellin ( 9 ). Besides the increase of the compounds within the leaf, a significant amount (ca. 20%) of the total furanocoumarins was deposited on the surface of the leaf. The two monomethoxy furanocoumarins, 7 and 8 , began to increase steadily and simultaneously within the leaf and on the leaf surface ca. 40 h after the onset of the jasmonic-acid stimulus. Within the leaf, the ratio 7/8 was ca. 1.3:1.0, while among the surface lipids 8 dominated ( 7/8 0.8:1.0), indicating that the export of the compounds to the surface is not a simple diffusive translocation along the oil-ducts. Females of the carrot fly (Diptera, Psilidae) responded with an increased oviposition to the altered leaf surface chemistry of the JA-treated celery plants. The effect shown for total leaves was corroborated by surrogate leaves treated with leaf-surface extracts of JA-induced leaves. Based on the known stimulation of oviposition by furanocoumarins, we conclude that the enhanced amount of furanocoumarins on the surface can explain the insects' preference for the JA-stimulated plants. This is the first report of a JA-induced change of the surface chemistry of a plant and an increase of the acceptability of treated leaves for a specialist insect, like the carrot fly.     

Chlorophyll Breakdown in Senescent Banana Leaves: Catabolism Reprogrammed for Biosynthesis of Persistent Blue Fluorescent Tetrapyrroles

Chlorophyll breakdown is a visual phenomenon of leaf senescence and fruit ripening. It leads to the formation of colorless chlorophyll catabolites, a group of (chlorophyll‐derived bilin‐type) linear tetrapyrroles. Here, analysis and structure elucidation of the chlorophyll breakdown products in leaves of banana (Musa acuminata) is reported. In senescent leaves of this monocot all chlorophyll catabolites identified were hypermodified fluorescent chlorophyll catabolites (hmFCCs). Surprisingly, nonfluorescent chlorophyll catabolites (NCCs) were not found, the often abundant and apparently typical final chlorophyll breakdown products in senescent leaves. As a rule, FCCs exist only fleetingly, and they isomerize rapidly to NCCs in the senescent plant cell. Amazingly, in the leaves of banana plants, persistent hmFCCs were identified that accounted for about 80 % of the chlorophyll broken down, and yellow leaves of M. acuminata display a strong blue luminescence. The structures of eight hmFCCs from banana leaves were analyzed by spectroscopic means. The massive accumulation of the hmFCCs in banana leaves, and their functional group characteristics, indicate a chlorophyll breakdown path, the downstream transformations of which are entirely reprogrammed towards the generation of persistent and blue fluorescent FCCs. As expressed earlier in related studies, the present findings call for attention, as to still elusive biological roles of these linear tetrapyrroles.     

MULCH SURFACE COLOR AFFECTS ACCUMULATION OF EPICUTICULAR WAX ON DEVELOPING LEAVES

Abstract— Leaf waxes are important to plant growth because they impede water loss and may influence entry of light. Leaf wax quantity and composition were studied in Capsicum annuum plants in trickle-irrigated field plots covered with white, black or red plastic mulches. The quantity of reflected blue light (BL) was greatest over white and about the same over black versus red surfaces; and reflected far-red to red ratios (FR/R) were about the same over white versus black and higher over red. The greatest quantity of total epicuticular wax developed on leaves of plants grown over white mulch (443 μg/cm²) while plants grown over black and red mulches had 229 and 227 μg/cm², respectively. When individual lipid classes were expressed as percentages of the totals, esters constituted the highest percentages over white and black surfaces while secondary free fatty alcohols dominated over red. The higher ester content of epicuticular wax on plants grown over black (versus red) was almost exactly equalled by increased contents of free fatty alcohols and free fatty acids in the epicuticular wax of plants grown over red mulch. We conclude that the total wax concentration on leaves of field-grown plants was influenced by quantity of BL, and the percentage of individual components was influenced by the FR/R ratio.     

A new linoleiyl arabinopyranoside from the bark of Bauhinia racemosa Lam and a new flavonoidal glycoside from the leaves of Cordia dichotoma Linn

Phytochemical investigation is very valuable for the ethnomedicinally important plants Bauhinia racemosa Lam (BR) and Cordia dichotoma Linn (CD) used for the cure of variety of ailments. This study was thus designed for phytochemical investigation of BR bark and CD leaves. Phytoconstituents were isolated from the methanolic extracts of the plants by column chromatography using silica gel as stationary phase. The structures had been established on the basis of their physicochemical and spectral data, i.e. IR, ¹H NMR, ¹³C NMR and MS. Elution of the columns with different solvents furnished six compounds (1–6) from the methanolic extract of BR bark and three compounds (7–9) from the methanolic extract of CD leaves which were structurally elucidated. The present phytochemical investigation reported several new compounds useful in increasing the existing knowledge of phytoconstituents from BR bark and CD leaves which is very valuable, as these drugs are used in the Indian traditional systems of medicine.     

Chemical and Biological insights of Ouratea hexasperma (A. St.-Hil.) Baill.: a source of bioactive compounds with multifunctional properties

The study aimed to evaluate in vitro antioxidant, anticholinesterase and antidiabetic properties of Ouratea hexasperma (A. St.-Hil.) Baill. The inflorescence methanol extract and the ethyl acetate fraction of leaves and stems reported the highest Relative Antioxidant Capacity Index (RACI), whereas the dichloromethane fraction of leaves was the best inhibitor of α-amylase and α-glucosidase. Trans-3-O-methyl-resveratrol-2-C-β-glucoside, lithospermoside, 2,5-dimethoxy-p-benzoquinone, lup-20(30)-ene-3β,28-diol, 7-O-methylgenistein, apigenin and luteolin and amentoflavone were isolated from O. hexasperma. Resveratrol derivative was isolated for the first time in Ochnaceae family. Luteolin, followed by apigenin, reported the highest Relative Antioxidant Capacity Index and they were also the best inhibitors of α-glucosidase enzyme.